<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #result{
            height: 100px;
            width: 200px;
            border: solid 1px #90b;
        }
    </style>
</head>
<body>
    <div id="result"></div>
    <script>
        const result = document.getElementById('result');
        window.onkeydown = function() {
            const xhr = new XMLHttpRequest();
            // 设置响应体数据类型
            xhr.responseType = 'json';
            xhr.open('GET', 'http://127.0.0.1:8000/json-server');
            xhr.send();
            xhr.onreadystatechange = function() {
                if(xhr.readyState === 4) {
                    if(xhr.status >= 200 && xhr.status < 300) {
                        // 手动转化数据
                        // let data = JSON.parse(xhr.response);
                        // result.innerHTML = data.name;
                        // 自动转化数据
                        result.innerHTML = xhr.response.name;
                    }
                }
            }
        }
    </script>
</body>
</html>